In Europe the digital TV standard for terrestrial broadcast is known as Digital Video Broadcast-Terrestrial (DVB-T). This standard adopts Coded OFDM (or COFDM) symbols and techniques to circumvent typical problems of terrestrial broadcast transmission. These problems include echoes, which result in Inter-Symbol Interference or ISI (with the previous symbol) and multi-path distortion, in addition to the distortion from frequency-independent AWGN.
Typically, the DVB-T standard contains COFDM symbols (i.e., data packets) which include a “cyclic prefix,” also referred to as a guard interval, to overcome echoes and ISI. There are generally no issues or problems on the transmission end with transmitting a symbol having a cyclic prefix. However, receiving a COFDM symbol having a guard interval and adhering to the DVB-T standard at a receiver has drawbacks that affect the quality of the signal. Removing the guard interval is not a viable option when using COFDM techniques because of echoes and ISI. The advantages of using COFDM for broadcasting digital media and the techniques themselves are explained in “The how and why of COFDM” by J. H. Stott (of BBC Research and Development), EBU Technical Review—Winter 1998, incorporated by reference herein for all purposes. Thus, it would be desirable for broadcasters to have receivers that are able to receive and process COFDM symbols while maintaining the high quality digital broadcasting capability of the DVB-T standard.